Damping thermoplastic elastomers

ABSTRACT

A thermoplastic elastomer compound includes styrenic block copolymer that is high vinyl styrene-(ethylene/butylene)-styrene block copolymer and high softening point tackifier. The high vinyl styrene-(ethylene/butylene)-styrene block copolymer has a Copolymer Tan Delta Peak Temperature and the thermoplastic elastomer compound has a Compound Tan Delta Peak Temperature. The Compound Tan Delta Peak Temperature is greater than the Copolymer Tan Delta Peak Temperature. The thermoplastic elastomer compound exhibits useful damping properties at or above room temperature while also advantageously possessing improved stability for processing and/or applications at high temperatures and upon exposure to weathering.

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional PatentApplication Ser. Nos. 62/114,708 filed on Feb. 11, 2015, and 62/114,701filed on Feb. 11, 2015, each of which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

This invention relates to thermoplastic elastomer compounds that exhibituseful damping properties such as vibration, sound, and/or impactdamping at or above room temperature.

BACKGROUND OF THE INVENTION

Demand exists in a variety of applications for materials that exhibitdamping properties. In general, damping is the dissipation of mechanicalenergy from a system. Damping can be important in applications such aselectronics, sound isolation, automotive and transportation, buildingand construction, household appliances, industrial equipment, firearms,healthcare and medical devices, and personal and/or sports protection.

The capacity of a material for damping is related to its peaktemperature of the tangent of delta (Tan Delta Peak Temperature), whichcan be determined by dynamic mechanical analysis (DMA) as described, forexample, by M. P. Sepe in “Thermal Analysis of Polymers”, Rapra ReviewReports, Vol. 8, No. 11, 1997, which is incorporated herein byreference. The tangent of delta (Tan Delta) of a material is the ratioof its loss modulus (E″) to its storage modulus (E′). Consequently, asthe value of Tan Delta increases, the response of the material isrelatively more viscous than it is elastic, which thus provides greaterdamping. When graphically depicted against temperature, a Tan Deltacurve includes a prominent peak at a particular temperature, which isthe Tan Delta Peak Temperature and also can be representative of orcomparable to the glass transition temperature (Tg) of the material. Ingeneral, a material with a Tan Delta Peak Temperature which isrelatively nearer to an application temperature, such as at or aboveroom temperature, will possess better damping properties than a materialwith a Tan Delta Peak Temperature which is relatively lower than theapplication temperature.

Thermoplastic elastomers (TPEs), which are polymer materials thatexhibit elasticity while remaining thermoplastic, can be used fordamping applications. Thermoplastic elastomers can include styrenicblock copolymers (SBC), thermoplastic vulcanizates (TPV), thermoplasticolefins (TPO), copolyesters (COPE), thermoplastic urethanes (TPU),copolyamides (COPA), and olefin block copolymers (OBC).

Some commercially available SBCs, such as HYBRAR 5127 available fromKuraray Co., Ltd., are known to exhibit vibration damping properties atroom temperature. HYBRAR 5127 has a Tan Delta Peak Temperature that isreported to be 20° C. (i.e., about room temperature). Although HYBRAR5127 can be formulated into conventional TPE compounds that exhibiteffective room temperature damping, it is a relatively low molecularweight and non-hydrogenated material and cannot withstand processing athigh temperatures required for some applications nor is it suitable forhigh temperature applications.

Other commercially available SBCs, such as HYBRAR 7125 available fromKuraray Co., Ltd., are hydrogenated and can withstand processing at thehigh temperatures. However, the Tan Delta Peak Temperature of HYBRAR7125 is reported to be −5° C. Disadvantageously, conventional TPEcompounds based on HYBRAR 7125 do not possess satisfactory dampingproperties at room temperature. As a further disadvantage, SBCsavailable under the HYBRAR brand can be more expensive than othercommercially available SBCs, which can make such HYBRAR brand SBCseconomically less desirable for some end-use applications.

Additionally, for some SBCs, it may be desirable to make the SBC softerby oil extension depending on processing and/or end-use applicationrequirements. For example, paraffinic oil can be used as plasticizer toselectively plasticize the soft blocks of SBCs. Although addingparaffinic oil to the SBC results in lower hardness and lower meltviscosity, which may be desirable, doing so also severely decreases theTan Delta Peak Temperature of the SBC, which negatively affects dampingproperties at room temperature.

SUMMARY OF THE INVENTION

Consequently, a need exists for TPE compounds that are capable of beingprocessed at relatively high temperatures or suitable for applicationsat relatively high temperatures while also exhibiting useful dampingproperties, such as damping properties at or above room temperature, andalso being economically viable for a broad scope of end-useapplications. Such a need exists especially for TPE compounds thatinclude plasticizer.

The aforementioned needs are met by one or more aspects of the presentinvention.

It has been found that, by adding high softening point tackifier tostyrenic block copolymer that is high vinylstyrene-(ethylene/butylene)-styrene block copolymer (high vinyl SEBS) toprovide a thermoplastic elastomer compound, the Copolymer Tan Delta PeakTemperature of the high vinyl SEBS can be shifted to a highertemperature (i.e., the Compound Tan Delta Peak Temperature) and,thereby, the damping capacity of the high vinyl SEBS can be increasedfor an intended end-use application at a given temperature, such as ator above room temperature. Surprisingly, the Copolymer Tan Delta PeakTemperature of the high vinyl SEBS can be shifted to a highertemperature even when the thermoplastic elastomer compound furtherincludes plasticizer, which is known to decrease Tan Delta PeakTemperature.

One aspect of the invention is a thermoplastic elastomer compound thatincludes high vinyl SEBS and high softening point tackifier. The highvinyl SEBS has a Copolymer Tan Delta Peak Temperature and the compoundhas a Compound Tan Delta Peak Temperature. The Compound Tan Delta PeakTemperature is greater than the Copolymer Tan Delta Peak Temperature.

Another aspect of the invention is a plastic article formed from theaforementioned thermoplastic elastomer compound.

A further aspect of the invention is a multi-component plastic articleincluding at least two components formed from different thermoplasticmaterials and in which at least one of the different thermoplasticmaterials is the aforementioned thermoplastic elastomer compound.

An even further aspect of the invention is a method for increasing thedamping capacity of a thermoplastic elastomer compound including astyrenic block copolymer that is high vinyl SEBS by further including ahigh softening point tackifier in the thermoplastic elastomer compound.

Features of the invention will become apparent with reference to thefollowing embodiments. There exist various refinements of the featuresnoted in relation to the above-mentioned aspects of the presentinvention. Additional features may also be incorporated in theabove-mentioned aspects of the present invention. These refinements andadditional features may exist individually or in any combination. Forinstance, various features discussed below in relation to any of thedescribed aspects of the present invention may be incorporated into anyof the described aspects of the present invention alone or in anycombination.

EMBODIMENTS OF THE INVENTION

In some embodiments, the present invention is directed to athermoplastic elastomer compound that includes styrenic block copolymerthat is high vinyl SEBS and high softening point tackifier. In otherembodiments, the present invention is directed to a plastic articleformed from the aforementioned thermoplastic elastomer compound. Infurther embodiments, the present invention is directed to amulti-component plastic article in which at least one thermoplasticcomponent is formed from the aforementioned thermoplastic elastomercompound. Required and optional features of these and other embodimentsof the present invention are described.

As used herein, the term “Compound Tan Delta Peak Temperature” means theTan Delta Peak Temperature for a thermoplastic elastomer compound of thepresent invention that comprises high softening point tackifier and highvinyl SEBS.

As used herein, the term “Copolymer Tan Delta Peak Temperature” meansthe Tan Delta Peak Temperature for the neat high vinyl SEBS; that is,for the high vinyl SEBS, itself, prior to combining it with any otheringredients of the thermoplastic elastomer compound of the presentinvention.

As used herein, the term “essentially free of” a certain componentmeans, in some embodiments, that no amount of that component isintentionally incorporated into a compound. In other embodiments, itmeans that less than 1 weight percent of the component is intentionallyincorporated into the compound; and, in other embodiments, it means thatless than 0.1 weight percent of the component is intentionallyincorporated into the compound; and, in other embodiments, it means thatless than 0.01 weight percent of the component is intentionallyincorporated into the compound; and, in other embodiments, it means thatless than 0.001 weight percent of the component is intentionallyincorporated into the compound.

As used herein, the term “high softening point tackifier” means atackifier having a softening point of at least 80° C. according to ASTM6493.

As used herein, the term “softening point” means a material softeningtemperature as measured by a ring and ball type method according to ASTM6493.

As used herein, the term “high vinyl” means that the vinyl content of astyrenic block copolymer (prior to hydrogenation) is greater than 50mole percent. For example, more than 50 mole percent of thepolybutadiene present in the midblock is polymerized at the 1,2-positionby driving the polymerization with addition of a polar compound, as iswell known by those of ordinary skill in the art. After hydrogenation ofthe high vinyl styrenic block copolymer, there is little or no vinylunsaturation remaining. Nonetheless, such a styrenic block copolymer,namely high vinyl SEBS, is still referred to as “high vinyl” because itis derived from a high vinyl precursor.

As used herein, “high vinyl SEBS” means high vinylstyrene-(ethylene/butylene)-styrene block copolymer.

As used herein, the term “low vinyl” means that the vinyl content of astyrenic block copolymer (prior to hydrogenation) is not greater than 50mole percent.

As used herein, the term “room temperature” means a range of temperatureof a defined environment, usually an indoor environment, which isgenerally considered comfortable for human habitation, and, can include,for example, any temperature ranging from about 15° C. to about 26° C.

As used herein, the term “Tan Delta” means the tangent of delta of amaterial and is the ratio of the material's loss modulus (E″) to thematerial's storage modulus (E′).

As used herein, the term “Tan Delta Peak Temperature” means thetemperature at which a prominent peak appears in a graphical depictionof Tan Delta against temperature for a material, as determined bydynamic mechanical analysis using TA Instruments Dynamic MechanicalAnalysis Model Q800 in “shear sandwich” mode and for a temperature scanfrom −40° C. to 100° C. increasing at a rate of 5° C. per minute andwith an oscillation frequency of 10 Hz.

Thermoplastic Elastomer Compound

In some embodiments, the present invention is directed to athermoplastic elastomer compound that includes high vinyl SEBS and highsoftening point tackifier.

It has been found that, by adding high softening point tackifier to highvinyl SEBS to provide a thermoplastic elastomer compound, the CopolymerTan Delta Peak Temperature of the high vinyl SEBS can be shifted to ahigher temperature (i.e., the Compound Tan Delta Peak Temperature). Thatis, for thermoplastic elastomer compounds of the present invention, theCompound Tan Delta Peak Temperature is greater than the Copolymer TanDelta Peak Temperature.

In some embodiments, the Compound Tan Delta Peak Temperature is at least−10° C. In other embodiments, the Compound Tan Delta Peak Temperature isat least 0° C. In further embodiments, the Compound Tan Delta PeakTemperature is at least room temperature. In even further embodiments,the Compound Tan Delta Peak Temperature is from about −10° C. to about70° C., and, in other embodiments, is from about 5° C. to about 50° C.

High Vinyl SEBS Styrenic Block Copolymer

Thermoplastic elastomer compounds of the present invention include oneor more styrenic block copolymer that is high vinyl SEBS.

Examples of commercially available high vinyl SEBS include one or moreof the KRATON brand, including the KRATON ERS brand, of styrenic blockcopolymers from Kraton Polymers LLC, such as grades G1641, G1642, G1643,G1645, MD6958, and MD6959. KRATON brand G series styrenic blockcopolymers are known to have glass transition temperatures (Tg) rangingfrom around −55° C. to around −38° C.

As used herein, “high vinyl” means that the vinyl content of thestyrenic block copolymer (prior to hydrogenation) is greater than 50mole percent. In some embodiments, the vinyl content of the styrenicblock copolymer is from about 55 to about 90 mole percent, and, infurther embodiments, from about 65 to about 90 mole percent.

The high vinyl SEBS has an ethylene/butylene midblock that is thehydrogenation product of 1,3-butadiene.

Suitable high vinyl SEBS include those as described in, for example,U.S. Pat. No. 5,777,031 to Djiauw et al. and U.S. Pat. No. 6,984,688 toGu, each of which is incorporated herein by reference.

It is to be understood that an isoprene midblock that is hydrogenated isconverted to an ethylene/propylene midblock. Similarly, it is to beunderstood that a butadiene midblock that is hydrogenated is convertedto an ethylene/butylene midblock.

In some embodiments, suitable high vinyl SEBS has a relatively lowweight average molecular weight. In other embodiments, suitable highvinyl SEBS has a relatively high weight average molecular weight. Forexample, suitable high vinyl SEBS can have weight average molecularweights in excess of 75,000 and preferably in excess of 200,000. In someembodiments, the styrenic block copolymer has a weight average molecularweight ranging from about 75,000 to about 1 million or from about 75,000to about 500,000. In other embodiments, the styrenic block copolymer hasa weight average molecular weight ranging from about 200,000 to about 1million or from about 200,000 to about 500,000.

The high vinyl SEBS has a Copolymer Tan Delta Peak Temperature. Asdiscussed above, by adding high softening point tackifier to high vinylSEBS to provide a thermoplastic elastomer compound, the Copolymer TanDelta Peak Temperature of the high vinyl SEBS can be shifted to a highertemperature (i.e., the Compound Tan Delta Peak Temperature).

It is believed that the high softening point tackifier is more effectiveat shifting the Copolymer Tan Delta Peak Temperature to a highertemperature for styrenic block copolymers having a Copolymer Tan DeltaPeak Temperature that is greater than about −40° C. but, for example,less than about −10° C., or, as a further example, less than about 0°C., or, as an even further example, less than room temperature, or, asyet a further example, less than a temperature greater than roomtemperature.

In some embodiments, high vinyl SEBS has a Copolymer Tan Delta PeakTemperature that is greater than about −40° C. but less than −10° C.,or, less than 0° C., or, less than room temperature, or, less than atemperature greater than room temperature.

In some embodiments, the thermoplastic elastomer compound can includeone or more other styrenic block copolymers in addition to the highvinyl SEBS. Non-limiting examples of other styrenic block copolymersinclude low vinyl styrene-ethylene/butylene-styrene (low vinyl SEBS),styrene-ethylene/propylene-styrene (SEPS),styrene-ethylene/ethylene/propylene-styrene (SEEPS),styrene-isobutylene-styrene (SIBS), styrene-butadiene-styrene (SBS),styrene-isoprene-styrene (SIS), and combinations thereof.

However, in further embodiments, the thermoplastic elastomer compound isessentially free of certain other styrenic block copolymers. Forexample, in some embodiments, the thermoplastic elastomer compound isessentially free of any high vinyl SEBS having a Copolymer Tan DeltaPeak Temperature that is less than about −40° C. and/or any otherstyrenic block polymers having a Copolymer Tan Delta Peak Temperaturethat is less than about −40° C.

In even further embodiments, the thermoplastic elastomer compound isessentially free of styrene-(ethylene-ethylene/propylene)-styrene blockcopolymer or low vinyl styrene-(ethylene/butylene)-styrene blockcopolymer or both. Some standard or low vinyl styrenic block copolymers,such as those available under the SEPTON brand from Kuraray Co., Ltd.and including SEPTON 4000 Series SEEPS copolymers, typically have aCopolymer Tan Delta Peak Temperature that is less than about −40° C.

In other embodiments, the thermoplastic elastomer compound isessentially free of hydrogenated styrene-isoprene-styrene blockcopolymer with hydrogenated vinylic isoprene midblock. Some commerciallyavailable examples of such styrenic block copolymers, such as thoseavailable from Kuraray Co., Ltd., under the HYBRAR brand, includinggrades 7125 and 7135, can be more expensive and thus economically lessdesirable for some end-use applications.

High Softening Point Tackifier

Thermoplastic elastomer compounds of the present invention include oneor more high softening point tackifiers.

By adding high softening point tackifier to styrenic block copolymerthat is high vinyl SEBS, the Copolymer Tan Delta Peak Temperature of thehigh vinyl SEBS can be shifted to a higher temperature (i.e., theCompound Tan Delta Peak Temperature).

High softening point tackifiers that are suitable for use in the presentinvention have a softening point of at least about 80° C. according toASTM 6493. In some embodiments, the softening point is at least 100° C.,and, in other embodiments, at least about 120° C., and, in furtherembodiments, at least about 140° C. In even further embodiments, thesoftening point ranges from about 80° C. to about 150° C.

Suitable high softening point tackifiers include those derived fromrosin feedstock, terpene feedstock, or hydrocarbon feedstock.Hydrocarbon-based high softening point tackifiers can be aliphatic oraromatic, and saturated or unsaturated.

Examples of commercially available high softening point tackifiersinclude hydrogenated hydrocarbon resins available under the ARKON brand,such as grades P100, P115, P125, and P140, from Arakawa ChemicalIndustries, Ltd.; hydrogenated hydrocarbon resins available under theEASTOTAC brand, such as grades H-125-W, H-140-W, and H-142-W, fromEastman Chemical Company; hydrogenated hydrocarbon resins availableunder the PLASTOLYN brand, such as grade R1140, from Eastman ChemicalCompany; and hydrogenated hydrocarbon resins available under theREGALREZ brand, such as grade 1139, from Eastman Chemical Company.

In some embodiments, the high softening point tackifier includes anamorphous hydrocarbon resin derived from aromatic hydrocarbon feedstock.In further embodiments, the high softening point tackifier is fullyhydrogenated and has a saturated cyclo-aliphatic structure.

In some embodiments, the high softening point tackifier has a weightaverage molecular weight ranging from about 400 to about 3,500. In otherembodiments, the high softening point tackifier has a weight averagemolecular weight ranging from about 1,000 to about 2,000.

High softening point tackifier is included in the thermoplasticelastomer compound of the present invention in amount ranging from about20 parts by weight to about 200 parts by weight, per 100 parts by weightof the styrenic block copolymer. In some embodiments, the amount of highsoftening point tackifier ranges from about 30 parts by weight to about150 parts by weight, per 100 parts by weight of the styrenic blockcopolymer.

It is believed that, in general, a relatively higher proportion of highsoftening point tackifier is required to shift the Tan Delta PeakTemperature to a higher temperature for styrenic block copolymer havinga relatively higher molecular weight. Conversely, it is believed that,in general, a relatively lower proportion of high softening pointtackifier is required to shift the Tan Delta Peak Temperature to ahigher temperature for styrenic block copolymer having a relativelylower molecular weight.

Care should be taken to ensure that the thermoplastic elastomer compoundof the present invention is formulated to provide properties desirablefor a TPE compound and not properties more commonly observed in adhesivecompositions. Generally, adhesive compositions are different from TPEcompounds at least because adhesive compositions typically arerelatively low viscosity compositions which do not possess the usefulmechanical properties of TPE compounds. Accordingly, even if up to about200 parts by weight of high softening point tackifier is used per 100parts by weight of styrenic block copolymer, the thermoplastic elastomercompound of the present invention is not an adhesive composition. Forexample, the thermoplastic elastomer compound is not tacky, or it is notsticky to the touch of a human hand.

Optional Plasticizer

In some embodiments, the thermoplastic elastomer compound furtherincludes plasticizer. Plasticizer can be used, for example, to adjustsoftness and/or improve flow or other properties of the thermoplasticelastomer compound.

Any conventional oil capable of plasticizing styrenic block copolymer,such as mineral oil, vegetable oil, synthetic oil, etc., can be used inthe present invention. Examples of commercially available oils includethose available under the PURETOL 380 brand from Petro-Canada, and thoseavailable under the PRIMOL 382 brand from ExxonMobil.

In some embodiments, plasticizers with a higher molecular weight thanthat of the aforementioned conventional oils can be used. Polyisobutene(PIB) is an example of such a plasticizer with a relatively highermolecular weight. For example, medium- to high-molecular weight PIB iscommercially available under the OPPANOL brand from BASF.

Optional Filler

In some embodiments, the thermoplastic elastomer compound furtherincludes inorganic filler.

Inorganic filler can be used, for example, to lower the cost and/orcontrol properties of the thermoplastic elastomer compound. In otherembodiments, the inorganic filler also can be used, for example, as amineral filler flame retardant.

Non-limiting examples of inorganic fillers include iron oxide, zincoxide, magnesium oxide, titanium oxide, zirconium oxide, titaniumdioxide, alumina, silica, silica-alumina, aluminum hydroxide, magnesiumhydroxide, calcium hydroxide, magnesium carbonate, calcium carbonate(heavy, light, colloidal), barium sulfate, calcium sulfate, sodiumsulfate, calcium sulfite, calcium silicate, calcium phosphate, magnesiumphosphate, talc, mica, kaolin, clay, wollastonite, hydrotalcite, glassbeads, glass powders, silica sand, silica rock, silicon nitride, quartzpowder, volcanic pumice, diatomaceous earth, white carbon, iron powderand aluminum powder.

In some embodiments, the inorganic filler is calcium carbonate, talc, ormixtures thereof.

Optional Secondary Polymer

In some embodiments, the thermoplastic elastomer compound furtherincludes secondary polymer. Secondary polymer should be compatible withthe styrenic block copolymer and can, for example, contribute toimproved processability or desirable physical properties, such ashardness, in the thermoplastic elastomer compound.

Suitable secondary polymer includes polyolefin-based resins, includinghomopolymers, copolymers, blends of polymers, mixtures of polymers,alloys of polymers, and combinations thereof.

Non-limiting examples of polyolefins suitable for use in the presentinvention include polyethylene (including low-density (LDPE),high-density (HDPE), ultra-high molecular weight (UHDPE),linear-low-density (LLDPE), very-low density, etc.), maleatedpolypropylene, polypropylene, polybutylene, polyhexalene, polyoctene,and copolymers thereof, olefin block copolymer such asethylene/alpha-olefin interpolymer, and ethylene-vinyl-acetate (EVA)copolymer. In some embodiments, high density polyethylene (HDPE) and/orpolypropylene (PP) are preferred. Such polyolefins are commerciallyavailable from a number of sources.

Suitable secondary polymer also includes rubber, such as butyl rubberand ethylene propylene diene monomer (EPDM) rubber. The rubber can becrosslinked or non-crosslinked.

Mixtures, blends, or alloys of secondary polymer include, for example, athermoplastic vulcanizate (TPV) that is a blend of a continuous phase ofa polyolefin such as polypropylene and a discontinuous phase of avulcanized rubber such as crosslinked EPDM.

Suitable secondary polymer also includes polyphenylene ethers (PPE).Non-limiting examples of types of PPE, sometimes also referred to aspolyphenylene oxide, can include poly(2,6-dimethyl-1,4-phenylene ether),poly(2,6-diethyl-1,4-phenylene ether),poly(2-methyl-6-ethyl-1,4-phenylene ether),poly(2-methyl-6-propyl-1,4-phenylene ether),poly(2,6-dipropyl-1,4-phenylene ether),poly(2-ethyl-6-propyl-1,4-phenylene ether),poly(2,6-dimethoxy-1,4-phenylene ether), poly(2,6-di(chloromethyl)-1,4-phenylene ether), poly(2,6-di(bromo methyl)-1,4-phenyleneether), poly(2,6-diphenyl-1,4-phenylene ether),poly(2,6-ditoluyl-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenyleneether), poly(2,6-dibenzyl-1,4-phenylene ether),poly(2,5-dimethyl-1,4-phenylene ether), and combinations thereof.

Optional Bonding Agent

In some embodiments in which the thermoplastic elastomer compound isovermolded onto a thermoplastic substrate, the thermoplastic elastomercompound further includes at least one bonding agent.

For embodiments in which the thermoplastic substrate is polyamide(nylon), suitable bonding agents include maleic anhydride functionalizedpolymers, such as maleic anhydride functionalized polyolefin and maleicanhydride functionalized styrenic block copolymer. For example, suitablemaleic anhydride functionalized polyolefins are described in U.S. Pat.No. 7,842,747 to Gu et al., which is incorporated herein by reference.

Examples of commercially available maleic anhydride functionalizedpolyolefin include those available under the EXXELOR brand fromExxonMobil Chemical; those available under the POLYBOND brand fromAddivant; and those available under the FUSABOND brand from DuPont.

Examples of commercially available maleic anhydride functionalizedstyrenic block copolymer include those available under the KRATON FGbrand, such as grades FG1901 and FG1924, from Kraton PerformancePolymers Inc.

For embodiments in which the thermoplastic substrate is a polyolefinsuch as polypropylene, suitable bonding agents include compatiblepolyolefins such as those described above as secondary polymers,including polypropylene. Commercially available examples includepolypropylene available under the BRASKEM H521 brand from BraskemAmerica Inc.

For embodiments in which the thermoplastic substrate is a anotherthermoplastic material such as thermoplastic polyurethane (TPU),polycarbonate (PC), polycarbonate/acrylonitrile butadiene styrene(PC/ABS), and polybutylene terephthalate/polycarbonate (PBT/PC),suitable bonding agents include compatible polymers such as TPU orcopolyester elastomer (COPE) or blends of TPU/COPE. Commerciallyavailable examples include TPU available under the ELASTOLLAN brand fromBASF.

Other Optional Additives

In some embodiments, the thermoplastic elastomer compound furtherincludes conventional plastics additives in an amount that is sufficientto obtain a desired processing or performance property for the compound.The amount should not be wasteful of the additive nor detrimental to theprocessing or performance of the compound. Those skilled in the art ofthermoplastics compounding, without undue experimentation but withreference to such treatises as Plastics Additives Database (2004) fromPlastics Design Library (elsevier.com), can select from many differenttypes of additives for inclusion into the compounds of the presentinvention.

Non-limiting examples of optional additives that can be included in thethermoplastic elastomer compounds of the present invention includeadhesion promoters; biocides; anti-fogging agents; anti-static agents;blowing and foaming agents; bonding agents and bonding polymers;dispersants; flame retardants and smoke suppressants; impact modifiers;initiators; lubricants; micas; pigments, colorants and dyes; processingaids; release agents; silanes, titanates and zirconates; slip andanti-blocking agents; stabilizers; stearates; ultraviolet lightabsorbers; viscosity regulators; waxes; and combinations of any of theaforementioned additives.

In some embodiments, the thermoplastic elastomer compound furtherincludes a physical foaming agent, such as carbon dioxide, nitrogen, orair, and/or a chemical foaming agent, such as organic or inorganiccompounds that release gases upon decomposition, and can be injectionmolded or extruded into a foamed TPE material.

Ranges of Ingredients in the TPE Compounds

Table 1 below shows the acceptable, desirable, and preferable ranges ofingredients for the thermoplastic elastomer compound of the presentinvention, based on 100 parts by weight of the styrenic block copolymerincluded in the thermoplastic elastomer compound.

The thermoplastic elastomer compound of the present invention cancomprise, consist essentially of, or consist of these ingredients. Anynumber between the ends of the ranges is also contemplated as an end ofa range, such that all possible combinations are contemplated within thepossibilities of Table 1 as embodiments of compounds for use in thepresent invention. Unless expressly stated otherwise herein, anydisclosed number is intended to refer to exactly the disclosed number,“about” the disclosed number, or both exactly the disclosed number and“about” the disclosed number.

TABLE 1 Thermoplastic Elastomer Compound (parts by weight per 100 partsby weight of SBC) Ingredient Acceptable Desirable Preferable StyrenicBlock Copolymer 100 100 100 High Softening Point Tackifier 20 to 200  30to 170 35 to 140 Optional Plasticizer 0 to 200 20 to 150 40 to 100Optional Filler 0 to 150  0 to 100 0 to 80 Optional Secondary Polymer 0to 300  0 to 200  0 to 150 Optional Bonding Agent 0 to 300  0 to 200  0to 150 Optional Other Additives 0 to 100 0 to 80 0 to 50

In some embodiments, especially those for low compression setapplications, the thermoplastic elastomer compound can include at leastabout 50 parts, or, at least about 70 parts, but less than about 100parts, or less than about 80 parts, by weight of high softening pointtackifier, based on 100 parts by weight of the styrenic block copolymerincluded in the thermoplastic elastomer compound. In furtherembodiments, it is possible to achieve desirable low compression set anduseful damping properties from thermoplastic elastomer compounds of thepresent invention that include less than about 40 weight percent, or, insome embodiments, less than about 35 weight percent, or, in otherembodiments, less than about 25 weight percent, or, in furtherembodiments, less than about 20 weight percent, of styrenic blockcopolymer.

In other embodiments, especially those for noise or sound dampingapplications, the thermoplastic elastomer compound can include at leastabout 20 parts, or, at least about 40 parts, but less than about 70parts, or, less than about 50 parts, by weight of high softening pointtackifier, based on 100 parts by weight of the styrenic block copolymerincluded in the thermoplastic elastomer compound.

In further embodiments, especially those for impact dampingapplications, the thermoplastic elastomer compound can include at leastabout 75 parts, or, at least about 90 parts, but less than about 150parts, or, less than about 110 parts, by weight of high softening pointtackifier, based on 100 parts by weight of the styrenic block copolymerincluded in the thermoplastic elastomer compound.

In even further embodiments, the thermoplastic elastomer compound caninclude less than 30 weight percent of high softening point tackifierbased on total weight of the compound. In even further embodiments, thethermoplastic elastomer compound can include less than 28 weight percentof high softening point tackifier based on total weight of the compound.

Processing

The preparation of thermoplastic elastomer compounds of the presentinvention is uncomplicated once the proper ingredients have beenselected. The compound of the present can be made in batch or continuousoperations.

Mixing in a continuous process typically occurs in an extruder that iselevated to a temperature that is sufficient to melt the polymer matrixwith addition of all additives at the feed-throat, or by injection orside-feeders downstream. Extruder speeds can range from about 200 toabout 700 revolutions per minute (rpm), and preferably from about 300rpm to about 500 rpm. Typically, the output from the extruder ispelletized for later extrusion, molding, thermoforming, foaming,calendering, and/or other processing into polymeric articles.

Subsequent extrusion, molding, thermoforming, foaming, calendering,and/or other processing techniques are well known to those skilled inthe art of thermoplastics polymer engineering. Without undueexperimentation but with such references as “Extrusion, The DefinitiveProcessing Guide and Handbook”; “Handbook of Molded Part Shrinkage andWarpage”; “Specialized Molding Techniques”; “Rotational MoldingTechnology”; and “Handbook of Mold, Tool and Die Repair Welding”, allpublished by Plastics Design Library (www.elsevier.com), one can makearticles of any conceivable shape and appearance using compounds of thepresent invention.

Usefulness of the Invention

In some embodiments, the present invention is directed to a plasticarticle formed from the thermoplastic elastomer compound as describedherein.

In other embodiments, the present invention is directed to amulti-component plastic article which includes at least two componentsformed from different thermoplastic materials one of which is thethermoplastic elastomer compound as described herein.

In further embodiments, the plastic article or a component of themulti-component plastic article can be shaped from the TPE compound bymolding, extruding, thermoforming, calendering, blow molding, and viaadditive 3-D manufacturing.

In even further embodiments, the present invention is directed to amethod for increasing the damping capacity of a thermoplastic elastomercompound including a styrenic block copolymer by further including ahigh softening point tackifier in the thermoplastic elastomer compound.

As discussed above, it has been found that, by adding high softeningpoint tackifier to styrenic block copolymer to provide a thermoplasticelastomer compound, the Copolymer Tan Delta Peak Temperature of thestyrenic block copolymer can be shifted to a higher temperature (i.e.,the Compound Tan Delta Peak Temperature). Advantageously, the dampingcapacity of the styrenic block copolymer can be increased for anintended end-use application at a given temperature, for example, atleast −10° C., or at least 0° C., or at room temperature, or greaterthan room temperature.

Accordingly, thermoplastic elastomer compounds of the present inventioncan be used for any plastic article or any component of amulti-component plastic article which needs physical properties of aTPE, such as flexibility, elongation, and/or a soft or silky feel, whilealso providing useful damping capacity for applications at temperaturesthat are, for example, at least −10° C., or at least 0° C., or at roomtemperature, or greater than room temperature. Additionally, thethermoplastic elastomer compounds of the present inventionadvantageously are capable of being processed at relatively hightemperatures, such as those required for overmolding.

Because of its usefulness and versatility, the thermoplastic elastomercompound of the present invention has potential for a variety of dampingapplications in many different industries, including but not limited to:automotive and transportation; household appliances; industrialequipment; electronics; acoustics; communications; healthcare andmedical; defense; firearms; security; personal safety; sportsprotection; and other industries or applications benefiting from thecompound's unique combination of properties, such as low compression setand/or sound damping and/or impact damping.

Compression set is the permanent deformation of a viscoelastic materialafter being subjected to a constant stress and an elevated temperature.Conventional vibration damping thermoplastic elastomer compoundstypically utilize low molecular weight styrenic block copolymers, suchas HYBRAR 5127 styrenic block copolymer. These conventional TPEcompounds tend to have high (i.e., poor) compression set, and, toachieve good damping, typically require in the TPE compound at least 40weight percent of styrenic block copolymer, which is a relativelyexpensive ingredient.

According to the present invention, it is possible to use high molecularweight styrenic block copolymers, which provide low compression set,while also achieving useful damping capacity at or above roomtemperature. In some embodiments, thermoplastic elastomer compounds ofthe present invention have a compression set (at 70° C. for 22 hoursaccording to ASTM D395) of less than 50%, and, in other embodiments,less than 40%, and, in further embodiments, less than 30%. Additionally,it is possible to achieve desirable low compression set and usefuldamping properties from thermoplastic elastomer compounds of the presentinvention that include less than about 40 weight percent, or, in someembodiments, less than about 35 weight percent, or, in otherembodiments, less than about 25 weight percent, or, in furtherembodiments, less than about 20 weight percent, of styrenic blockcopolymer.

Sound damping is highly desirable for many applications including, forexample, for high quality headphones and/or earphones or for speakersand components such as rims or gaskets for speakers. In the acousticsindustry, sound damping is can be assessed by a hitting test and arubbing test. For the hitting test, a cable (e.g., for wired headphonesor earphones) is repeatedly hit by a wooden rod to simulate actual usageconditions. For the rubbing test, the wooden is moved back and forthalong the cable. The acoustic responses or effective sound pressurelevels generated by the hitting and rubbing are determined by anelectronic artificial ear according to methodologies such as IEC 711 orevaluated by a human qualified as a so-called “golden ear”.

Because damping is frequency specific, vibration damping and sounddamping can occur at different frequencies. As such, a material that isgood for vibration damping is not necessarily good for sound damping.Indeed, conventional TPE compounds including low molecular weightstyrenic block copolymers, such as HYBRAR 5127 styrenic block copolymer,possess good room temperature vibration damping properties. However, thesame TPE compounds are not very effective at sound damping for wiredheadphone and/or earphone cable applications according to the hittingand rubbing tests.

According to the present invention, it is possible to provide excellentsound damping performance according to the hitting and rubbing testswhile also achieving useful vibration damping properties. For example,an article formed from the TPE compound of the present invention, inresponse to a noise stimulus, can produce an effective sound pressurelevel according to IEC 711 that is at least 80% lower, and, in someembodiments, at least 90% lower, than an effective sound pressure levelaccording to IEC 711 produced by a control article in response to thesame noise stimulus.

Impact damping, such as for sports protection, typically requiresmaterials with a relatively low hardness (e.g., having a Shore Ahardness of less than about 50) that have good outdoor (e.g., UV andthermal) stability and are additionally capable of withstanding numerousrepeated industrial washing machine cycles (e.g., 150 cycles of 70° C.washing and 90° C. drying) while maintaining dimensional stability(e.g., without experiencing substantial shrinkage). Conventional TPEcompounds including low molecular weight styrenic block copolymers, suchas HYBRAR 5127 styrenic block copolymer, possess good room temperaturevibration damping properties. However, the same TPE compounds have poorUV and thermal stability and cannot withstand repeated industrialwashing machine cycles.

According to the present invention, it is possible to provide usefulimpact damping properties at room temperature with a thermoplasticelastomer compound that also has good UV and thermal stability and canwithstand repeated industrial washing machine cycles. Additionally, ascompared to ethylene-vinyl acetate (EVA) and/or urethane (PU) thermalset foams, which are bench mark materials for impact damping sportsprotection applications, thermoplastic elastomer compounds of thepresent invention can provide relative design freedom for sportsequipment manufacturers (e.g., the TPE compound of the present inventioncan be molded with complex geometry) as well as relative additionalcomfort for sports equipment users (e.g., the TPE compound of thepresent invention can be softer and more flexible than EVA foam).Articles for impact protection made from the TPE compound of the presentinvention can be softer, more compact, and more flexible, and, thus,more comfortable, than conventional impact protection articles made fromEVA and/or PU.

Additionally, if desirable for any application, the thermoplasticelastomer compound can be overmolded onto a substrate. In someembodiments, the substrate is a thermoplastic substrate such aspolyamide (nylon) or polyolefin (e.g., polypropylene) or anotherthermoplastic material such as thermoplastic polyurethane (TPU),polycarbonate (PC), polycarbonate/acrylonitrile butadiene styrene(PC/ABS), or polybutylene terephthalate/polycarbonate (PBT/PC).According to the present invention, the thermoplastic elastomer compoundovermolded onto a thermoplastic substrate has 90 degree peel strengthof, in some embodiments, greater than about 8 pounds per inch, and, inother embodiments, greater than about 10 pounds per inch.

EXAMPLES

Non-limiting examples of thermoplastic elastomer compounds of variousembodiments of the present invention are provided.

Examples Showing Effect of High Softening Point Tackifier

Table 2a below shows sources of ingredients for the thermoplasticelastomer compounds of Examples 1 to 16.

TABLE 2a Chemical Brand Source Styrene- SEPTON 4055 Kuraray(ethylene/ethylene/propylene)- styrene block copolymer High vinylstyrene- KRATON G1642 Kraton (ethylene/butylene)-styrene block copolymer(Low molecular weight) High vinyl styrene- KRATON G1641 Kraton(ethylene/butylene)-styrene block copolymer (High molecular weight) Highvinyl styrene- KRATON MD6958 Kraton (ethylene/butylene)-styrene blockcopolymer (Very high molecular weight) High vinyl styrene- KRATON MD6959Kraton (ethylene/butylene)-styrene block copolymer (Very high molecularweight) White mineral oil 380 vis USP white oil (numerous) Hydrocarbonresin PLASTOLYN R1140 Eastman Chemical Polyethylene resin DOWLEX 2035Dow Chemical Calcium carbonate (limestone) VICRON 25-11 SpecialtyMinerals Wax KEMAMIDE E PMC Biogenix Antioxidant IRGANOX 1010 BASF

Table 2b below shows the formulations and certain properties of Examples1 to 5.

TABLE 2b Example 1 2 Ingredient Parts Wt. % Parts Wt. % SEPTON 4055 257.78 25 7.78 KRATON G1642 75 23.34 0 0 KRATON G1641 0 0 75 23.34 KRATONMD6958 0 0 0 0 KRATON MD6959 0 0 0 0 380 vis USP white oil 80 24.89 8024.89 PLASTOLYN R1140 60 18.67 60 18.67 DOWLEX 2035 40 12.45 40 12.45VICRON 25-11 40 12.45 40 12.45 KEMAMIDE E 0.7 0.22 0.7 0.22 IRGANOX 10100.7 0.22 0.7 0.22 TOTAL 321.4 100.00 321.4 100.00 Tan Delta Peak Height0.48 0.40 (unitless) Example 3 4 5 Ingredient Parts Wt. % Parts Wt. %Parts Wt. % SEPTON 4055 25 7.78 25 7.78 100 31.11 KRATON G1642 0 0 0 0 00 KRATON G1641 0 0 0 0 0 0 KRATON MD6958 75 23.34 0 0 0 0 KRATON MD69590 0 75 23.34 0 0 380 vis USP white oil 80 24.89 80 24.89 80 24.89PLASTOLYN R1140 60 18.67 60 18.67 60 18.67 DOWLEX 2035 40 12.45 40 12.4540 12.45 VICRON 25-11 40 12.45 40 12.45 40 12.45 KEMAMIDE E 0.7 0.22 0.70.22 0.7 0.22 IRGANOX 1010 0.7 0.22 0.7 0.22 0.7 0.22 TOTAL 321.4 100.00321.4 100.00 321.4 100.00 Tan Delta Peak Height 0.30 0.40 0.25(unitless)

Table 2c below shows the formulations and certain properties of Examples6 to 9.

TABLE 2c Example 6 7 8 9 Ingredient Parts Wt. % Parts Wt. % Parts Wt. %Parts Wt. % KRATON 100 33.18 100 31.11 100 29.29 100 27.67 MD6958 380vis USP 80 26.54 80 24.89 80 23.43 80 22.14 white oil PLASTOLYN 40 13.2760 18.67 80 23.43 100 27.67 R1140 DOWLEX 40 13.27 40 12.45 40 11.72 4011.07 2035 VICRON 25-11 40 13.27 40 12.45 40 11.72 40 11.07 KEMAMIDE E0.7 0.23 0.7 0.22 0.7 0.21 0.7 0.19 IRGANOX 0.7 0.23 0.7 0.22 0.7 0.210.7 0.19 1010 TOTAL 301.4 100.00 321.4 100.00 341.4 100.00 361.4 100.00Tan Delta Peak 0.65 0.70 0.85 0.85 Height (unitless) Compound Tan 3 2 716 Delta Peak Temperature (deg C.)

Table 2d below shows the formulations and certain properties of Examples10 to 13.

TABLE 2d Example 10 11 12 13 Ingredient Parts Wt. % Parts Wt. % PartsWt. % Parts Wt. % KRATON 100 33.18 100 31.11 100 29.29 100 27.67 MD6959380 vis USP 80 26.54 80 24.89 80 23.43 80 22.14 white oil PLASTOLYN 4013.27 60 18.67 80 23.43 100 27.67 R1140 DOWLEX 40 13.27 40 12.45 4011.72 40 11.07 2035 VICRON 25-11 40 13.27 40 12.45 40 11.72 40 11.07KEMAMIDE E 0.7 0.23 0.7 0.22 0.7 0.21 0.7 0.19 IRGANOX 0.7 0.23 0.7 0.220.7 0.21 0.7 0.19 1010 TOTAL 301.4 100.00 321.4 100.00 341.4 100.00361.4 100.00 Tan Delta Peak 0.5 0.70 0.70 0.75 Height (unitless)Compound Tan −8 3 18 24 Delta Peak Temperature (deg C.)

Table 2e below shows the formulations and certain properties of Examples14 to 16.

TABLE 2e Example 14 15 16 Ingredient Parts Wt. % Parts Wt. % Parts Wt. %KRATON G1641 100 27.67 100 29.29 100 31.11 380 vis USP white oil 8022.14 80 23.43 80 24.89 PLASTOLYN R1140 100 27.67 80 23.43 60 18.67DOWLEX 2035 40 11.07 40 11.72 40 12.45 VICRON 25-11 40 11.07 40 11.72 4012.45 KEMAMIDE E 0.7 0.19 0.7 0.21 0.7 0.22 IRGANOX 1010 0.7 0.19 0.70.21 0.7 0.22 TOTAL 361.4 100.00 341.4 100.00 321.4 100.00 Tan DeltaPeak Height 0.85 0.75 0.70 (unitless) Compound Tan Delta 21 11 3 PeakTemperature (deg C.)

Examples of TPE Compounds with Low Compression Set

Table 3a below shows sources of ingredients for the thermoplasticelastomer compounds of Examples 17 to 18, which can be useful forend-use applications requiring low compression set and good dampingcapacity (e.g., vibration and/or sound damping).

TABLE 3a Chemical Brand Source High vinyl styrene-(ethylene/butylene)-KRATON Kraton styrene block copolymer (Very high MD6958 molecularweight) White mineral oil PAROL 500 Petro-Canada Polyphenylene ether LXR040C Bluestar New Chemical Materials Hydrocarbon resin PLASTOLYN EastmanR1140 Chemical HDPE SCLAIR 2908 NOVA Chemicals Wax KEMAMIDE E PMCBiogenix Antioxidant IRGANOX BASF 1010

Table 3b below shows the formulations and certain properties of Examples17 to 18.

TABLE 3b Example 17 18 Ingredient Parts Wt. % Parts Wt. % KRATON MD6958100 32.13 100 29.74 PAROL 500 80 25.71 80 23.80 LXR 040C 30 9.64 30 8.92PLASTOLYN R1140 75 24.10 75 22.31 SCLAIR 2908 25 8.03 50 14.87 KEMAMIDEE 0.5 0.16 0.5 0.15 IRGANOX 1010 0.7 0.22 0.7 0.21 TOTAL 311.2 100.00336.2 100.00 Hardness (Shore A) 28 48 Tensile (psic) 500 610 Elongation(%) 560 590 Compression set (%) 21 28 (70 deg C., 22 h) (ASTM D395)

Examples of TPE Compounds for Sound Damping

Table 4a below shows sources of ingredients for the thermoplasticelastomer compound of Example 19, which can be useful for sound and/ornoise damping end-use applications.

TABLE 4a Chemical Brand Source High vinyl styrene-(ethylene/butylene)-KRATON Kuraray styrene block copolymer (Low G1642 molecular weight)White mineral oil 550 vis USP (numerous) white oil Polyphenylene etherLXR 040C Bluestar New Chemical Materials Hydrocarbon resin PLASTOLYNEastman R1140 Chemical Polypropylene D036W6 Braskem Wax KEMAMIDE E PMCBiogenix Antioxidant IRGAFOS 168 BASF Antioxidant IRGANOX BASF 1010

Table 4b below shows the formulations and certain properties of Example19.

TABLE 4b Example 19 Ingredient Parts Wt. % KRATON G1642 47 41.01 550 visUSP white oil 10 8.73 LXR 040C 20 17.45 PLASTOLYN R1140 20 17.45 D036W617 14.83 KEMAMIDE E 0.3 0.26 IRGAFOS 168 0.15 0.13 IRGANOX 1010 0.150.13 TOTAL 114.6 100.00 Hardness (Shore A) 65 Tensile (psic) 1830Elongation (%) 600

Examples of TPE Compounds for Impact Damping (e.g., for Personal and/orSports Protection)

Table 5a below shows sources of ingredients for the thermoplasticelastomer compound of the Example 20, which can be useful for impactdamping for personal and/or sports protection end-use applications.

TABLE 5a Chemical Brand Source Styrene-(ethylene/ethylene/propylene)-SEPTON 4077 Kuraray styrene block copolymer Hydrogenatedstyrene-isoprene-styrene HYBRAR 7135 Kuraray block copolymer withhydrogenated vinylic isoprene midblock High vinylstyrene-(ethylene/butylene)- KRATON Kraton styrene block copolymer (Veryhigh MD6958 molecular weight) White mineral oil 380 vis USP (numerous)white oil Hydrocarbon resin PLASTOLYN Eastman R1140 ChemicalPolypropylene H521 Braskem Calcium carbonate (limestone) VICRON 25-11Specialty Minerals Wax KEMAMIDE E PMC Biogenix Antioxidant IRGAFOS 168BASF Antioxidant IRGANOX 1010 BASF

Table 5b below shows the formulations and certain properties of Example20.

TABLE 5b Example 20 Ingredient Parts Wt. % KRATON MD6958 100 27.67 380vis USP white oil 80 22.14 PLASTOLYN R1140 100 27.67 H521 40 11.07VICRON 25-11 40 11.07 KEMAMIDE E 0.6 0.17 IRGAFOS 168 0.4 0.11 IRGANOX1010 0.4 0.11 TOTAL 361.4 100.00 Hardness (Shore A) 45 Tensile (psic)650 Elongation (%) 800

Examples of Damping TPE Compounds for Overmolding onto a Nylon Substrate

Table 6a below shows sources of ingredients for the thermoplasticelastomer compound of Example 21, which can be useful for dampingend-use applications involving overmolding onto a nylon substrate.

TABLE 6a Chemical Brand Source High vinyl styrene-(ethylene/butylene)-KRATON Kraton styrene block copolymer (Very high MD6958 molecularweight) White mineral oil 550 vis USP (numerous) white oil Hydrocarbonresin PLASTOLYN Eastman R1140 Chemical Maleic anhydride functionalizedKRATON Kraton styrenic block copolymer FG1924 Maleic anhydridefunctionalized EXXELOR ExxonMobil polypropylene VA1801 Chemical LDPENA206 Equistar Calcium carbonate (limestone) VICRON 25-11 SpecialtyMinerals Wax KEMAMIDE B PMC Biogenix Antioxidant IRGANOX 1010 BASF

Table 6b below shows the formulations and certain properties of Example21.

TABLE 6b Example 21 Ingredient Parts Wt. % KRATON MD6958 120 24.86 550vis USP 45 9.32 white oil PLASTOLYN R1140 80 16.57 KRATON FG1924 25 5.18EXXELOR VA1801 71 14.71 NA206 10 2.07 VICRON 25-11 130 26.93 KEMAMIDE B0.9 0.19 IRGANOX 1010 0.9 0.19 TOTAL 482.8 100.00 Hardness 40 (Shore A)Tensile (psic) 400 Elongation (%) 550 Overmold nylon substrate (30%glass filled, nylon 6) OM 90 degree >16 peel strength (lb/in)

Without undue experimentation, those having ordinary skill in the artcan utilize the written description of the present invention, includingthe Examples, to formulate thermoplastic elastomer compounds thatexhibit useful damping properties, such as damping properties at orabove room temperature, while also being capable of processing atrelatively high temperatures, including those conditions required forovermolding.

All documents cited in the Embodiments of the Invention are, in relevantpart, incorporated herein by reference; the citation of any document isnot to be construed as an admission that it is prior art with respect tothe present invention.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of the present invention.

What is claimed is:
 1. A thermoplastic elastomer compound comprising:(a) high vinyl styrene-(ethylene/butylene)-styrene block copolymerhaving a Copolymer Tan Delta Peak Temperature; and (b) tackifier havinga softening point of at least about 80° C. according to ASTM 6493; andwherein the compound has a Compound Tan Delta Peak Temperature, and theCompound Tan Delta Peak Temperature is greater than the Copolymer TanDelta Peak Temperature.
 2. The compound of claim 1, wherein the compoundis essentially free of styrene-(ethylene-ethylene/propylene)-styreneblock copolymer and low vinyl styrene-(ethylene/butylene)-styrene blockcopolymer.
 3. The compound of claim 1, wherein the compound isessentially free of hydrogenated styrene-isoprene-styrene blockcopolymer with hydrogenated vinylic isoprene midblock.
 4. The compoundof claim 1, wherein the Copolymer Tan Delta Peak Temperature is greaterthan −40° C. but less than −10° C.
 5. The compound of claim 1, whereinthe Compound Tan Delta Peak Temperature is at least −10° C.
 6. Thecompound of claim 1, wherein the tackifier has a softening point rangingfrom about 80° C. to about 150° C. according to ASTM
 6493. 7. Thecompound of claim 1, wherein the tackifier has a weight averagemolecular weight ranging from about 400 to about 3,500.
 8. The compoundof claim 1, wherein the tackifier comprises a saturated cyclo-aliphaticamorphous hydrocarbon resin.
 9. The compound of claim 1, wherein thetackifier is present in an amount ranging from about 20 parts by weightto about 200 parts by weight, per 100 parts by weight of the styrenicblock copolymer.
 10. The compound of claim 1, wherein the compoundfurther comprises plasticizer.
 11. The compound of claim 1, wherein thecompound further comprises secondary polymer.
 12. The compound of claim1, wherein the compound further comprises filler.
 13. The compound ofclaim 1, wherein the compound further comprises at least one additiveselected from the group consisting of adhesion promoters; biocides;anti-fogging agents; anti-static agents; blowing and foaming agents;bonding agents and bonding polymers; dispersants; flame retardants andsmoke suppressants; impact modifiers; initiators; lubricants; micas;pigments, colorants and dyes; processing aids; release agents; silanes,titanates and zirconates; slip and anti-blocking agents; stabilizers;stearates; ultraviolet light absorbers; viscosity regulators; waxes; andcombinations of any of the aforementioned additives.
 14. The compound ofclaim 1, wherein the compound comprises: (a) 100 parts by weight of thestyrenic block copolymer; (b) from about 20 to about 200 parts by weightof the tackifier; (c) from 0 to about 200 parts by weight of optionalplasticizer; (d) from 0 to about 300 parts by weight of optionalsecondary polymer; (e) from 0 to about 150 parts by weight of optionalfiller; and (f) from 0 to about 100 parts by weight of optional otheradditives.
 15. A plastic article formed from the compound of claim 1.